Circuit breaker and safety interlock for modular power supply

ABSTRACT

A circuit breaker assembly with a pivotally mounted indicator flag and latch member adapted to engage and releasably lock a manual control handle of the circuit breaker in an open position. The handle in the closed position shields from view the indicator flag and in the open position exposes the indicator flag to view, thereby providing a visual indication of when the circuit breaker is open. An output terminal strip of the circuit breaker has a cover positioned with respect to the handle so that it can be removed only when the handle is in the open position. The circuit breaker is mountable adjacent to a power supply module and mechanically interlocks therewith so that the module cannot be removed from the frame in which it is carried prior to removal of the terminal cover and thus prior to opening of the circuit breaker.

United StatesPatent Plantholt et al.

[4 Jan. 25, 1972 CIRCUIT BREAKER AND SAFETY INTERLOCK FOR MODULAR POWERSUPPLY lnventors: Robert G. Plantholt, Rochester; Michael A. Koltuniak,Warren, both of Mich.

Controlled Power' Corporation, Farmington, Mich.

Filed: Feb. 6, 1970 Appl. No.: 9,179

Assignee:

References Cited UNITED STATES PATENTS 4/1933 Willoughby ..200/50.ll2/l941 Pierce etal. ..337/47 Jacks et al. ..200/50.l Groves ..200/50.l

[5 7 ABSTRACT A circuit breaker assembly with a pivotally mountedindicator flag and latch member adapted to engage and releasably lock amanual control handle of the circuit breaker in an open position. Thehandle in the closed position shields from view the indicator flag andin the open position exposes the indicator flag to view, therebyproviding a visual indication of when the circuit breaker is open. Anoutput terminal strip of the circuit breaker has a cover positioned withrespect to the handle so that it can be removed only when the handle isin the open position. The circuit breaker is mountable adjacent to apower supply module and mechanically interlocks therewith so that themodule cannot be removed from the frame in which it is carried prior toremoval of the terminal cover and thus prior to opening of the circuitbreaker.

15 Claims, 8 Drawing Figures PATENTEUJANZSIQYZ 3.637.960

sum 1 0r 2 P P" I Jll l Jll I PH 911 DI] C v INVENTORS ROBERT C.PLANTHOLT MICHAEL A. KO LTUNIAK ATTORNEYS mmmm 7 3637360 sum 2 OF 2INVENTORS I ROBERT G. PLANTHOLT MODULE H TO 1 P05 UN LOCK MICHAEL A.KOLTUNIAK ATTORNEYS l CIRCUIT BREAKER AND SAFETY INTERLOCK FOR MODULARPOWER SUPPLY This invention relates to electrical circuit breakers andmore particularly to a circuit breaker for a modular power supply-Objects of this invention are to provide a circuit breaker for a modularpower supply which l provides a purely mechanial highly visibleindicator that the breaker is open, (2) automatically locks in the openposition so that the breaker cannot be accidentally closed, (3) preventsits associated power supply module from being removed from its framewhile the circuit breaker is closed thereby providing a safetyinterlock, and (4) has only a few comparatively simple component partswhich can be readily molded or cast and hence is of economicalconstruction and assembly and is relatively maintenance free.

These and other objects, features and advantages of this invention aredisclosed in this specification and the accompanying drawings in which:

FIG. 1 is a front elevational view of a plurality of circuit breakersand their associated power supply modules mounted in stacked arrays in aframe to provide a modular power supply system.

FIG. 2 is a fragmentary front elevational view on an enlarged scale of acircuit breaker and associated power supply module illustrating the wayin which the module is carried by the frame.

FIG. 3 is a fragmentary sectional view on line 3-3 of FIG. 2illustrating some of the details of construction of the circuit breakerassembly with a handle shown in the closed position in solid lines andin the open position in phantom.

FIG. 4 is a fragmentary sectional view similar to FIG. 3 showing thehandle of the circuit breaker in the open position in solid line andintermediate the open and closed positions in phantom.

FIG. 5 is a fragmentary front elevational view of the circuit breakerassembly of FIG. 2 with the terminal cover panel removed and the circuitbreaker handle in the open position thereby exposing the indicator flagand latch member to plain view.

FIG. 6 is a perspective view of the indicator flag and latch member ofthe circuit breaker assembly.

FIG. 7 is a sectional view on line 77 of FIG. 6 showing thecross-sectional configuration of the indicator flag and latch member.

FIG. 8 is a fragmentary sectional view on line 8-8 of FIG. 2

showing the interlocking of the power supply module with the terminalcover panel.

Referring to the drawings:

FIG. 1 illustrates a modular power supply system designated generally as10 with a frame 12 adapted to slidably receive and carry a plurality ofindividual power supply modules 14. A circuit breaker assembly 16 isassociatedwith each power supply module 14. Power supply modules 14 andcircuit breakers 16 are arranged in frame 12 in three verticallyextending columns each containing seven modules and seven circuitbreakers. A panel 18 with an air vent 20 is attached to the side offrame 12 and encloses the control circuitry for the three columns ofpower supply modules 14.

As shown in FIG. 2, each power supply module 14 has a front spill cover22 with vents 24 therein secured by screws 26 to a chassis or carriage28 with two generally parallel spacedapart opposed outwardly extendingshoulders 30 thereon (only one of which is shown in FIG. 2). Each powersupply module 14 is carried by and slides into and out of frame 12 on apair of ways 32 secured to frame 12 and underlying shoulders 30 ofchassis 28. Each pair of ways 32 are generally in opposed spaced-apartparallel relationship and extend horizontally substantially the fulldepth of frame 12.

As shown in FIGS. 2, 5 and 8, circuit breaker assembly 16 has a'mounting panel 34 secured to frame 12 as by two screws 35 (FIG. 5) andsuch additional screws (not shown) as required. Mounting panel 34 has alower generally rectangular pan-shaped section 36, a central generallyrectangular opening 38, and a generally flat upper portion 40. Flatportion 40 of mounting panel 34 has an electrical terminal block orstrip 42 thereon and preferably integral therewith. A rectangularpan-shaped cover 44 overlies terminal block 42 and the upper portion 40of mounting panel 34 and is secured in place by two screws 46, the upperof which is shown in FIG. 2 and the lower of which is shown in hiddenlines in FIGS. 3 and 4.

As shown in FIGS. 3, 4 and 8, a three-phase circuit breaker 48 issecured to the rear face of mounting panel 34 by screws 50 with itsthree actuating arms 52 extending into opening 38 of the mounting panel.Arms 52 manually openthe contacts of circuit breaker 48 when moved tothe downward position shown in phantom in FIG. 3 and close the contactswhen moved upward to the solid line position shown in FIG. 3. Circuitbreakers of this general type are disclosed in expired Wilkins U.S. Pat.No. 2,360,922 issued Oct. 24, 1944 and unexpired Holiday US. Pat. No.3,141,082 issued July 14, I964 and are manufactured and soldcommercially by Heinemann Electric Company, Trenton, NJ. under CatalogNo. CD3-Z28 -2. A handle 54 with three pockets 56 in one end thereofreceives and firmly engages the protruding ends of all three arms 52.Handle 54 is secured to arms 52 by pin 58 extending transversely throughboth the arms and the handle so the arms will move in unison to assurethat the contacts for all three phases or lines of circuit breaker 48open and close substantially simultaneously.

An indicator flag and latch member 60 is pivotally mounted in opening 38of front panel 34 to swing away from and into locking engagement withabutments 62 on handle 54. As shown in FIGS. 6 and 7, member 60 has ashaft 64 with reduced diameter end portions or pins 66 and shoulders 68and an axially aligned and radially extending generally rectangular flatsheet 70 providing a flag or indicator. A short tab 72 for rotatingshaft 64 projects at a right angle from flag 70 and is connected theretoadjacent the shaft. Flag and latch member 60 is rotatably carried onmounting panel 34 by pins 66 extending through a pair of slots 74 insidewalls 76 of opening 38 in panel 34. Pins 66 are retained in slots 74by front face 78 of circuit breaker 48 bearing on shaft 64. Shoulders 68of shaft 64 bear on walls 76 and thus limit the axial movement of flagand latch member 60 in opening 38. As shown in FIGS. 3 and 4, handle 54has a bottom wall 82 with a V-shaped cross section, laterally spacedsidewalls 84, and end walls 86 and 88 defining a pocket 90. Pocket 90 isadapted to receive and overlie or shield from view flag 70 when handle54 is in the upward position shown in solid line in FIG. 3. Wall 88 ofhandle 54 provides a cam surface 92 which engages flag 70, when handle54 is in a position shown in phantom in FIG. 4, to swing the membercounterclockwise after it disengages from locking abutment 62.

When circuit breaker assembly 16 and its associated power supply module14 are installed in frame 12 of the modular power supply system, athree-phase source of electrical energy for the input of power supplymodule 14 is connected to one of the contacts of each set of circuitbreaker 48. The other contact of each set is connected through multiwirecable 94 (FIG. 8) to the terminals of junction or terminal block 42.Power supply module 14 is connected through circuit breaker 48 to itssource of input of electrical energy through leads 96 terminating inwasher lugs 98 connected to the terminals of terminal block 42 by screws100. As shown in FIGS. 3 and 8, handle 54 overlies terminal cover 44 andthe lower one of its associated screws 46 so that cover 44 cannot beremoved and access gained to terminal block 42 unless handle 54 is inthe downward position. Thus access to terminal strip 42 cannot be gainedunless circuit breaker 48 is in the open position so that there is nopower or electrical energy at terminal block 42.

Power supply module 14 is mechanically interlocked with cover 44 by aconduit 102 so that module 14 cannot be removed from frame 12 untilcover 44 is removed. Conduit 102 is fixed to and preferably integralwith front panel 22 of module 14 and has a flange 104 at its free end.Conduit 102 has a generally U-shaped cross section and extends through aU-shaped opening 106 (FIG. 4) in sidewall 108 of cover 44 with flange104 engaging the interior of sidewall 108. Since the lower screw 46 andhence cover 44 cannot be removed unless breaker 48 is open, module "14cannot be removed from frame 12 until circuit breaker 48 has beenopened. The present invention also contemplates a mechanical interlockdirectly between module 14 and handle 54 to open circuit breaker 48 whenmodule 1 4 is removed from frame 12. This can be achieved by fixing arod or shaft (not shown) to module 14 so that it extends generallyhorizontally between handle 54 and mounting panel 34. Although theillustrated embodiment is preferred, both arrangements provide safetyinterlocks which reduce the risk of electrical shock and injury toservice and maintenance personnel.

In operating circuit breaker assembly 16, when handle 54 is in the downor solid line position (shown in FIG. 4) the contacts of circuit breaker48 are open. Due to the force of gravity indicator and latch member 60assumes the position shown in FIG. 4 with flag portion 70 extendingvertically downward with its free edge overlying and in close proximityto abutments 62 of handle 54. When flag 70 is in this position, itprovides a latch cooperating with abutment 62 to lock handle 54 in thedown position and thus prevent the contacts of circuit breaker 48 frombeing closed. As shown in FIG. 5, when handle 54 is in the down positionflag 70 is'exposed to view from the front of mounting panel 34 and thusgives a visual indication that the circuit breaker is open and hence itsassociated power supply module is turned off or not operating. Ifdesired flag 70 can be colored a bright red and terminology as indicatedin FIG. added to further assist in determining when module 14 is off.The ability to promptly determine when a power supply module 14 is offor inoperative is particularly important in modular power supply systemsbecause such systems are designed so that the remaining power supplymodules automatically can, under certain conditions, assume the loadwhich was in part carried by a module that becomes inoperative.

To close the contacts of circuit breaker 48 pressure is manually appliedin the direction of the arrow in FIG. 4 to the underside of tab 72 ofindicator and latch member 64 to swing the free edge of flag 70counterclockwise and out of latching engagement with abutments 62 ofhandle 54 and then handle 54 is moved generally counterclockwise to theupward position shown in solid line in FIG. 3 to close the contacts ofcircuit breaker 48. As shown in FIG. 4, once flag 70 disengages fromabutments 62 and handle 54 is moved slightly upward cam surface 92engages the underside of flag 70 and cams the flag in a counterclockwisedirection to assure that handle 54 can be moved upward without furtherinterference by flag 70. As handle 54 nears the end of its upward strokeflag 70 is cammed counterclockwise by bottom wall 82 of handle 54 (asshown in solid line in FIG. 3). As shown in FIGS. 2 and 3, when handle54 is in the fully upward position it completely overlies and shieldsflag 70 so that it cannot be viewed from the front of circuit breakerassembly 16. Thus indicator or flag 70 is only visible when handle 54 isin the down position so that the contacts of circuit breaker 48 are openand its associated module 14 is off.

The handle 54, flag and latch member 60, terminal cover panel 44, andmounting panel 34 of circuit breaker assembly 16 can all be molded of anABS self-extinguishing plastic material and thus are of economicalconstruction. To further facilitate the economy of construction andassembly terminal block 42 can be integrally molded with mounting panel34 and a standardized commercially available circuit breaker 48 can beutilized in manufacture and assembly of the circuit breaker apparatus ofthis invention.

We claim:

1. A circuit breaker assembly comprising: an electric circuit breakerhaving at least one pair of contacts and at least one arm movable to afirst position wherein said contacts are open and to a second positionwherein said contacts are closed, a

handle connected adjacent one end thereof to said arm and movabletherewith to corresponding first and second positions to open and closesaid contacts,and indicator flag means movably mounted in said circuitbreaker assembly and operative to releasably lock said arm in said firstposition, said flag means comprising a shaft mounted in said circuitbreaker assembly for rotary movement about its longitudinal axis and agenerally rectangular panel connected to said shaft and extendinggenerally axially thereof and radially therefrom, at least one abutmenton said handle adjacent one end thereof adapted to be engaged by saidflag means to releasably lock said arm in its first position, saidhandle being arranged and constructed to overlie said flag means toshield said flag means from view from a front side of said assembly whensaid arm and said handle are in their respective second positions and toexpose said flag means to view from said front side of said assemblywhen said arm and said handle are in their respective first positions,and wherein said handle has a pocket therein adapted to receive at leasta portion of said flag means when said handle is in its said secondposition.

2. The circuit breaker assembly set forth in claim 1 wherein said handlehas a cam surface adjacent said abutment on said one end of said handle,said carn surface being adapted to engage and rotate said panel whensaid handle moves from its first to its second position.

3. The circuit breaker assembly set forth in claim 1 wherein said handleis arranged to move in an upward direction from its said first positionto its said second position and in a downward direction from its saidsecond positions to its said first position, and wherein said shaft ispivotally mounted in said circuit breaker assembly above said arm andadjacent said handle so that said handle engages said panel to retainsaid panel in a raised position when said handle is in its said secondposition and so that said panel is free to pivot downwardly due togravity when said handle is moved to its said first position.

4. The circuit breaker assembly set forth in claim 1 wherein said shaftis mounted in said circuit breaker assembly so that its longitudinalaxis is transverse to the direction of movement of said handle, saidpanel has a free edge remote from said shaft adapted to engage saidabutment to releasably lock said handle in its first position and saidpanel is arranged to be pivoted out of engagement with said abutment sothat said handle is free to be moved to its second position.

5. A circuit breaker assembly comprising: an electric circuit breakerhaving a housing, at least one pair of contacts and actuator means, saidactuator means having handle means operable from a front face of saidhousing and movable to a first position to open said contacts and to asecond position to close said contacts, said handle means further havinga shield portion arranged and constructed so that when said handle meansis in said second position said shield portion covers and is spacedforwardly of at least a portion of said front face, said assemblyfurther comprising combined indicator and latch means, means mountingsaid combined means in said circuit breaker assembly for movement to afirst position and to a second position, and wherein said combined meansis disposed in its first position to engage said actuator means andrestrain movement of said handle means from its first position to itssecond position, said combined means is further disposed in its firstposition to provide a clear visual indication that said contacts areopen when said handle means is in its first position, and said combinedmeans is disposed in its second position in the space between said frontface portion and said shield portion when said handle means is in itssecond position so as to 1 be hidden from view.

6. The assembly set forth in claim 5 wherein said combined indicator andlatch means comprises a panel pivotally mounted in said circuit breakerassembly for rotation about an axis that is generally parallel to saidfront face, said panel having a free edge remote from said axis adaptedto rotate to a position engaging said actuator means to restrainmovement of said handle means from its first position to its secondposition.

7. The circuit breaker assembly set forth in claim 5 wherein said handlemeans is mounted to pivot in an upward direction from said firstposition to said second position and in a downward direction from saidsecond position to said first position, and wherein said combinedindicator and latch means comprises a panel pivotally mounted in saidcircuit breaker assembly adjacent said handle means for rotation aboutan axis that is transverse to the direction of movement of said handlemeans, said panel being disposed so that said handle means engages saidpanel to retain said panel in a raised position when said handle meansis in its second position and so that said panel is free to pivotdownwardly due to gravity when said handle means is moved to said firstposition.

8. The circuit breaker assembly set forth in claim 7 wherein said panelengages said actuator means when said handle means is in its firstposition to restrain movement of said handle means from its firstposition to its second position, and wherein said combined indicator andlatch means further comprises a tab accessible when said panel is inengagement with said actuator means and operatively connected to saidpanel so that said panel can be disengaged from said actuator means bymoving said tab.

9. The circuit breaker assembly set forth in claim 7 wherein the pivotalmounting for said panel comprises a shaft and said panel has a free edgeremote from said shaft adapted to engage an abutment on said handlemeans when said handle means is in its first position thereby releasablylocking said handle means in itsfirst position and wherein said panel isarranged to be pivoted out of engagement with said abutment so that saidhandle means is free to be moved to its second position.

10. The circuit breaker assembly set forth in claim 5 further comprisingelectrical terminal means for connection to electrical wiring, saidterminal means being accessible from the front of said circuit breakerassembly to facilitate connection of said wiring, a movable coverenclosing said terminal means to prevent access to said terminal meanswhen said cover is in a closed. position, releasable fastener means forreleasably locking said cover in its closed position, said fastenermeans being located in the space between said front face portion andsaid handle means when said handle means is in its second position withsaid handle means overlying said fastener means to prevent accessthereto when said handle means is in its second position.

ll. In combination, a frame having a plurality of openings thereinadapted to slideably receive and support a plurality of power supplymodules, a plurality of power supply modules disposed in respectiveopenings in said frame, a plurality of circuit breaker assembliesmounted on said frame with each assembly disposed adjacent a front endof a respective associated module, each of said modules being adapted tobe removed from said frame by sliding motion relative to its associatedcircuit breaker assembly, each of saidcircuit breaker assembliescomprising a housing, at least one pair of contacts and actuator means,said actuator means having handle means operable from a front face ofsaid housing and movable to a first position to open said contacts andto a second position to close said contacts, terminal means in saidcircuit breaker assembly, electrical wiring connecting said terminalmeans in each circuit breaker assembly to its respective associatedmodule and adapted to supply power thereto when said contacts are closedand releasable mechanical interlock means interengaging each circuitbreaker assembly and its respective associated module to restrainremoval of said associated module from said frame and wherein saidinterlock means includes means for disengaging said interlock means whensaid handle means is moved to its first position.

12. The combination set forth in claim 11 wherein each circuit breakerassembly further comprises a movable cover overlying said terminal meansto prevent access thereto when said cover is closed and permit access tosaid terminal means when said cover is opened, and wherein each moduleinterlock means comprises said cover and a rigid member interengagedbetween a module and said cover of an associated circuit breakerassembly when said cover is closed to restrain motion of said rigidmember, said rigid member being adapted to be disengaged when said coveris opened.

13. The combination set forth in claim 12 wherein said means fordisengaging said mechanical interlock means comprises releasablefastener means for holding said cover in its closed position and therebymaintain said interlock means engaged, and wherein said handle means isarranged and constructed so that when said handle means is in its secondposition said handle means covers said releasable fastener means toprevent access thereto.

14. The combination set forth in claim 12 wherein said rigid membercomprises a conduit for said electrical wiring between a module and saidterminal means in its associated circuit breaker assembly.

15. A circuit breaker assembly comprising: an electric circuit breakerhaving a housing, at least one pair of contacts and actuator means, saidactuator means having handle means operable from a front face of saidhousing and movable to a first position to open said contacts and to asecond position to close said contacts, said handle means further havinga shield portion arranged and constructed so that when said handle meansis in said second position said shield portion overlies and is spacedforwardly of at least a portion of said front face, said assemblyfurther comprising electrical terminal means for connection toelectrical wiring, said terminal means being accessible from the frontof said circuit breaker assembly to facilitate connection of saidwiring, movable cover means enclosing said terminal means to preventaccess to said terminal means when said cover means is in a closedposition and permit access to said terminal means when said cover meansis in an open position, and releasable fastener means for releasablylocking said cover means in its closed position, said fastener meansbeing located in the space between said front face portion and saidhandle means when said handle means is in its second position so thatsaid handle means overlies said fastener means to prevent access theretowhen said handle means is in its second position.

1. A circuit breaker assembly comprising: an electric circuit breakerhaving at least one pair of contacts and at least one arm movable to afirst position wherein said contacts are open and to a second positionwherein said contacts are closed, a handle connected adjacent one endthereof to said arm and movable therewith to corresponding first andsecond positions to open and close said contacts, and indicator flagmeans movably mounted in said circuit breaker assembly and operative toreleasably lock said arm in said first position, said flag meanscomprising a shaft mounted in said circuit breaker assembly for rotarymovement about its longitudinal axis and a generally rectangular panelconnected to said shaft and extending generally axially thereof andradially therefrom, at least one abutment on said handle adjacent oneend thereof adapted to be engaged by said flag means to releasably locksaid arm in its first position, said handle being arranged andconstructed to overlie said flag means to shield said flag means fromview from a front side of said assembly when said arm and said handleare in their respective second positions and to expose said flag meansto view from said front side of said assembly when said arm and saidhandle are in their respective first positions, and wherein said handlehas a pocket therein adapted to receive at least a portion of said flagmeans when said handle is in its said second position.
 2. The circuitbreaker assembly set forth in claim 1 wherein said handle has a camsurface adjacent said abutment on said one end of said handle, said camsurface being adapted to engage and rotate said panel when said handlemoves from its first to its second position.
 3. The circuit breakerassembly set forth in claim 1 wherein said handle is arranged to move inan upward direction from its said first position to its said secondposition and in a downward direction from its said second positions toits said first position, and wherein said shaft is pivotally mounted insaid circuit breaker assembly above said arm and adjacent said handle sothat said handle engages said panel to retain said panel in a raisedposition when said handle is in its said second position and so thatsaid panel is free to pivot downwardLy due to gravity when said handleis moved to its said first position.
 4. The circuit breaker assembly setforth in claim 1 wherein said shaft is mounted in said circuit breakerassembly so that its longitudinal axis is transverse to the direction ofmovement of said handle, said panel has a free edge remote from saidshaft adapted to engage said abutment to releasably lock said handle inits first position and said panel is arranged to be pivoted out ofengagement with said abutment so that said handle is free to be moved toits second position.
 5. A circuit breaker assembly comprising: anelectric circuit breaker having a housing, at least one pair of contactsand actuator means, said actuator means having handle means operablefrom a front face of said housing and movable to a first position toopen said contacts and to a second position to close said contacts, saidhandle means further having a shield portion arranged and constructed sothat when said handle means is in said second position said shieldportion covers and is spaced forwardly of at least a portion of saidfront face, said assembly further comprising combined indicator andlatch means, means mounting said combined means in said circuit breakerassembly for movement to a first position and to a second position, andwherein said combined means is disposed in its first position to engagesaid actuator means and restrain movement of said handle means from itsfirst position to its second position, said combined means is furtherdisposed in its first position to provide a clear visual indication thatsaid contacts are open when said handle means is in its first position,and said combined means is disposed in its second position in the spacebetween said front face portion and said shield portion when said handlemeans is in its second position so as to be hidden from view.
 6. Theassembly set forth in claim 5 wherein said combined indicator and latchmeans comprises a panel pivotally mounted in said circuit breakerassembly for rotation about an axis that is generally parallel to saidfront face, said panel having a free edge remote from said axis adaptedto rotate to a position engaging said actuator means to restrainmovement of said handle means from its first position to its secondposition.
 7. The circuit breaker assembly set forth in claim 5 whereinsaid handle means is mounted to pivot in an upward direction from saidfirst position to said second position and in a downward direction fromsaid second position to said first position, and wherein said combinedindicator and latch means comprises a panel pivotally mounted in saidcircuit breaker assembly adjacent said handle means for rotation aboutan axis that is transverse to the direction of movement of said handlemeans, said panel being disposed so that said handle means engages saidpanel to retain said panel in a raised position when said handle meansis in its second position and so that said panel is free to pivotdownwardly due to gravity when said handle means is moved to said firstposition.
 8. The circuit breaker assembly set forth in claim 7 whereinsaid panel engages said actuator means when said handle means is in itsfirst position to restrain movement of said handle means from its firstposition to its second position, and wherein said combined indicator andlatch means further comprises a tab accessible when said panel is inengagement with said actuator means and operatively connected to saidpanel so that said panel can be disengaged from said actuator means bymoving said tab.
 9. The circuit breaker assembly set forth in claim 7wherein the pivotal mounting for said panel comprises a shaft and saidpanel has a free edge remote from said shaft adapted to engage anabutment on said handle means when said handle means is in its firstposition thereby releasably locking said handle means in its firstposition and wherein said panel is arranged to be pivoted out ofengagement with said abutment so that said handle means is free to bemoved to its second position.
 10. The circuit breaker assembly set forthin claim 5 further comprising electrical terminal means for connectionto electrical wiring, said terminal means being accessible from thefront of said circuit breaker assembly to facilitate connection of saidwiring, a movable cover enclosing said terminal means to prevent accessto said terminal means when said cover is in a closed position,releasable fastener means for releasably locking said cover in itsclosed position, said fastener means being located in the space betweensaid front face portion and said handle means when said handle means isin its second position with said handle means overlying said fastenermeans to prevent access thereto when said handle means is in its secondposition.
 11. In combination, a frame having a plurality of openingstherein adapted to slideably receive and support a plurality of powersupply modules, a plurality of power supply modules disposed inrespective openings in said frame, a plurality of circuit breakerassemblies mounted on said frame with each assembly disposed adjacent afront end of a respective associated module, each of said modules beingadapted to be removed from said frame by sliding motion relative to itsassociated circuit breaker assembly, each of said circuit breakerassemblies comprising a housing, at least one pair of contacts andactuator means, said actuator means having handle means operable from afront face of said housing and movable to a first position to open saidcontacts and to a second position to close said contacts, terminal meansin said circuit breaker assembly, electrical wiring connecting saidterminal means in each circuit breaker assembly to its respectiveassociated module and adapted to supply power thereto when said contactsare closed and releasable mechanical interlock means interengaging eachcircuit breaker assembly and its respective associated module torestrain removal of said associated module from said frame and whereinsaid interlock means includes means for disengaging said interlock meanswhen said handle means is moved to its first position.
 12. Thecombination set forth in claim 11 wherein each circuit breaker assemblyfurther comprises a movable cover overlying said terminal means toprevent access thereto when said cover is closed and permit access tosaid terminal means when said cover is opened, and wherein each moduleinterlock means comprises said cover and a rigid member interengagedbetween a module and said cover of an associated circuit breakerassembly when said cover is closed to restrain motion of said rigidmember, said rigid member being adapted to be disengaged when said coveris opened.
 13. The combination set forth in claim 12 wherein said meansfor disengaging said mechanical interlock means comprises releasablefastener means for holding said cover in its closed position and therebymaintain said interlock means engaged, and wherein said handle means isarranged and constructed so that when said handle means is in its secondposition said handle means covers said releasable fastener means toprevent access thereto.
 14. The combination set forth in claim 12wherein said rigid member comprises a conduit for said electrical wiringbetween a module and said terminal means in its associated circuitbreaker assembly.
 15. A circuit breaker assembly comprising: an electriccircuit breaker having a housing, at least one pair of contacts andactuator means, said actuator means having handle means operable from afront face of said housing and movable to a first position to open saidcontacts and to a second position to close said contacts, said handlemeans further having a shield portion arranged and constructed so thatwhen said handle means is in said second position said shield portionoverlies and is spaced forwardly of at least a portion of said frontface, said assembly further comprising electrical terminal means forconnection to electrical wiring, said termiNal means being accessiblefrom the front of said circuit breaker assembly to facilitate connectionof said wiring, movable cover means enclosing said terminal means toprevent access to said terminal means when said cover means is in aclosed position and permit access to said terminal means when said covermeans is in an open position, and releasable fastener means forreleasably locking said cover means in its closed position, saidfastener means being located in the space between said front faceportion and said handle means when said handle means is in its secondposition so that said handle means overlies said fastener means toprevent access thereto when said handle means is in its second position.